Labor is demanding Immigration Minister Scott Morrison give a full explanation about what he knew about a riot on Manus Island, after backtracking on claims a death occurred outside Australia's detention centre.

Mr Morrison now says most of the "riotous behaviour" that resulted in the death of an Iranian man and left 62 other asylum seekers injured happened inside the Papua New Guinea facility.

"The further information I have now received casts further doubt on the initial advice that his injuries were sustained outside the centre," he said in a statement issued just before 9pm on Saturday.

Immigration Minister Scott Morrison: Admits the information he gave on the Manus riot was wrong.

Labor frontbencher and former immigration minister Chris Bowen said the minister had a "lot of explaining to do".

"These are difficult circumstances, and as a former immigration minister I think the primary responsibility on Scott Morrison is to be up front with the Australian people, to be transparent," Mr Bowen told ABC TV on Sunday.

"And if he thinks a written statement at 9 o'clock on a Saturday night is being transparent, then he is sadly mistaken."

He called on Mr Morrison to say when he found out his previous claim about the riot was wrong.

"He should be up front with the Australian people about exactly when he was informed that what he had previously said was so completely and grievously incorrect," Mr Bowen said.

An independent investigation into the death of 23-year-old Reza Berati at Manus Island is expected to take several months.

Mr Morrison said the inquiry would also examine the actions of G4S, which handed control of the centre to Transfield Services on Saturday.

Both firms have promised to co-operate with the inquiry.

Greens immigration spokeswoman Sarah Hanson-Young repeated her call for the centre to be closed.

"The security of refugees and staff cannot be guaranteed, even inside the camp," she said in a statement.

Senior Liberal frontbencher Christopher Pyne said Coalition government MPs backed the government's hardline policy on asylum seeker boat arrivals that denies them any chance of settlement in Australia.

"It is a tough policy ... but we want to send a very clear message that we will protect our borders," he told Sky News.

Mr Bowen said Labor still viewed the Manus Island centre, which it reopened in government, as an important part of a suite of measures to discourage asylum seekers from making the dangerous boat journey to Australia from Indonesia.

"The measure is an important one, but it has got to be run competently," he said.

"The government has to be in control of the situation."

The Greens have called for Prime Minister Tony Abbott to sack Mr Morrison.

"The Prime Minister must sack the minister and close his cruel refugee prisons immediately,” Greens Leader Christine Milne said.

“Tony Abbott had a direct line of duty of care to Reza Berati and he is now dead," Senator Milne said.

"He must take personal responsibility. Blaming the victims of this tragedy is cowardice."